actually the LPF on the radio will control the lows being sent to the door speakers. and Msall's response was a more detailed version of mine. "too high volume; too much gain"



in any case, hopefully it was fixed.

 

That's how you tune your amp. If the distortion is coming from your amp then check it for a switch that has low-pass, high-pass, or off. Run high-pass for mids and highs, off if you're running a full-range setup or tuning everything from your headunit, and low-pass for subs. If you set it for LP then it will eliminate higher frequencies from going into the subs, something that subs can't effectively do because they move too much air to match the tiny wavelengths of higher frequencies.

If the distortion is coming from your door speakers, then your bass level might be too high. If you have a stock headunit, then turning your bass down will probably result in a bass reduction in your subs, all you gotta do is adjust your gain and bass boost (but don't run boost at high volume levels). If you have distortion with an aftermarket headunit, then look for your HPF. Most people mistake the LPF on the HU with the HPF. LPF eliminates frequencies higher than a set amount so it doesn't reach your subs. HPF (or the high pass filter) eliminates frequencies lower than a designated number as to remove bass frequencies from the door speakers. In my opinion, Pioneer headunits are awesome for HPF and LPF, but many other aftermrket HUs have this. Your subs should be the only audio components reproducing bass, and you door speakers should be the only audio components reproducing your mids and highs.

 

First things first. The amp isnt going to put out enough power to those Alpines (if they are the 2007 model) they are power hungry!!!

But you need to set your amp to HP.

n00b way: (MOST should do it this way)
0) Get a CD you really know and have it be very bass and highs heavy. ONE OF THE HARDEST SONGS/DISCS YOU WILL LISTEN TO

1) Start with the gains all the way down.
2) Set xover around 65 (for 6.5) and 75 for the (5x7).
3) Turn the radio up to abt 3/4 volume.

4) Slowly add in the front speakers until speakers just start to clip then back off about 1/8 turn.
4a) If mids start to distort then turn xover up until that is gone.

5) Add in back spks until you just start to notice the rear fill.
5a) If mids start to distort then turn xover up until that is gone.
6) Enjoy and tweek with other songs.

Pro way: (Much more in depth. PROS ONLY)
0) Get a CD with a 1kHz 0db sine sweep.
0) Get a radioshack amplified speaker
0) Get a RCA to mini with male and female ends.
0) Make a 10:1 step down.

1) Turn off all equalizers on radio. bass, EQ settings... etc.
2) Make sure everything is unplugged from radio.
3) Plug radioshack spk into back of HU.
4) Turn up until HU clips. Remember that level and KEEP IT THERE.
5) Go to next device (amps or EQ's ...etc. )
5a) going to use a EQ here.

6) Plug the Speaker into the output of the EQ.
7) Adjust gains to just before it clips.

8) Go to your amps
9) Install your 10:1 in between the amp and the Speakers.
10) Adjust gains until it clips then back down.

11) System is set.

P.S. With subs use a 40 Hz track. With tweeters use a 4kHz track.

 

No, the LPF will not control the lows being sent to the door speakers. That is the job of a HPF.

HPF: High Pass Filter (will let higher frequencies pass but cut lower freqs out) 20kHz > 70Hz
LPF: Low Pass Filter (will let lower freqs pass and cut higher freqs out) 20kHz < 70Hz
BPF: Band Pass Filter (will let certain mid freqs through and cut the higher and lower freqs out) 20kHz < 1kHz > 70Hz
NPF: Notch Pass Filter (will let highs and lows play but cut a certain mid freq out) 20kHz > 1kHz < 70Hz
APF: All Pass Filter (will let all freqs through) 20kHz = 70kHz

 

I used 5khz for tweeters, 1khz for mids and 100hz for subs. the mini amp cant really do 40hz to an audible level, even 100hz you really gotta listen for it.

 

You guys kick *** to offer all of this great advice! I bought a used truck with a bunch of audio stuff hooked up, but sounded like complete dog crap! I read 1000 posts here, dialed in my amp (mostly) and now my stereo sounds pretty damn good. Of course I want more bass and power, etc, but it's a far cry from what it was. It was almost un-listenable two weeks ago. Good stuff here....